This invention relates to windshield wiper arrangements for vehicles, such as motor vehicles, and to methods for manufacturing such arrangements.
Windshield wiper arrangements for vehicles are usually provided with a rack-and-pinion drive or a lever system. Windshield wiper arrangements having a lever system include a mounting for a drive comprising a wiper motor, a gear unit and a rotating lever arm that can be positioned on the vehicle body and generally also have two bearing brackets spaced at a distance from the mounting and the drive can be located between the bearing brackets or in the vicinity of one of the bearing brackets. A wiper arm drive shaft for each of the bearing brackets has an angularly fixed oscillating lever on the side opposite that wiper arm that is connected in an articulated manner to the lever arm by a link rod. With this arrangement, the rotary motion of the lever arm is converted into a reciprocating motion of each oscillating lever and thus of the wiper arm so that the wiper arms oscillate in synchronism.
The drive mounting can have a hollow shape or an open shape with an attached mounting plate upon which the drive elements are mounted and to which the bearing brackets, as externally manufactured cast parts, are attached by screws or swaging.
The manufacture of such conventional windshield wiper arrangements is accomplished by the manufacture of individual components, including the mounting, the mounting plate and the bearing brackets, and the subsequent assembly of these components into a unit. The unit is inserted in the vehicle and the wiper arms are then installed. It is apparent that the complexity of manufacture and assembly of conventional wiper arrangements is relatively great.
Accordingly, it is an object of the present invention to provide a windshield wiper arrangement for vehicles and a method for making it which overcomes the disadvantages of the prior art.
Another object of the invention is to provide a windshield wiper arrangement for vehicles, specifically motor vehicles, that can be manufactured with reduced complexity and hence less expensively, and a corresponding manufacturing method.
These and other objects of the invention are attained by providing a windshield wiper arrangement having a drive mounting which is a structural part with integral bearing brackets produced by internal high-pressure forming. This one-piece component is made in essentially one process step. Costly cast parts are no longer required. Moreover, assembly costs are reduced considerably, in part because tolerance adherence problems during assembly of the bearing brackets are eliminated. The arrangement is compact and has better power transmission.
The bearing brackets and the drive mount can be composed of opposed tubular projections extending essentially perpendicularly to the longitudinal axis of the structural part in order to increase the stability of the arrangement of the bushings and the drive.
The bushings can be pressed into the appropriate bearing brackets, which optimizes their fit but is also advantageous in connection with increased stability since the bushings pass completely through the tubular part. It is also particularly advantageous for the drive to be attached directly to the mounting, which is accomplished through mounting the gear unit, which is smaller than the motor, on the drive mounting.
This results in a windshield wiper arrangement that, as a whole, takes up relatively little space in the vehicle.
The tubular projection on the wiper side of each bearing bracket can be longer than the opposite projection on the oscillating arm side. This produces a better fit of the bushings pressed into the bearing brackets and has a favorable effect on the stability of the assembly which is especially necessary in the region of the reciprocating wiper arms.
The windshield wiper arrangement is manufactured in accordance with the invention by cold forming the mounting, including the bearing brackets and a drive mount, in one piece from a tubular semi finished part with internal high-pressure forming.
In this process the semi finished part can be placed in a form with a pressure surface having the shape of the mounting to be formed, with pairs of opposed, cup-like recesses which are essentially radial to the longitudinal axis of the mounting in the predetermined regions of the drive and the bearing brackets. The tubular semi finished part is subsequently subjected to high pressure by a pressure-transfer medium introduced into its interior, causing the tube walls to be pressed against the pressure surface on all sides and forced into the recesses in order to form tubular projections.
A bushing can be driven into the projections on opposite sides of the mounting that form a bearing bracket, and the gear unit housing for the gear unit arranged on the wiper motor can be pressed into the projections that form the drive mount, obviating the need for an additional attachment.